Leopard RAM upgrade on iMac G5 PPC

[M AUSTEN]

Hi,

I have one of the first iMac G5 ppc.  it currently has
512Mb RAM AND i would like to upgrade to 1Gb to run
Leopard more effectivly.

Can I do this myself and how:? or do i need to find an
Apple dealer?

Any help much appreciated.

Mark